Cement compositions with improved fluid loss characteristics and methods of cementing in surface and subterranean applications

ABSTRACT

An improved fluid loss control additive and methods of using such compositions in surface and subterranean applications are provided. A method of cementing in a subterranean formation, that comprises providing a cement composition that comprises a cement, water, and a fluid loss control additive, the fluid loss control additive comprising an acrylic acid copolymer derivative, an iron compound, and at least one of a hydratable polymer or a dispersant, placing the cement composition into the subterranean formation, and permitting the cement composition to set therein, is provided. Also provided are methods of reducing the fluid loss from a cement composition, cement compositions, and fluid loss control additives.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No. 10/891,384 entitled “Compositions Comprising Set Retarder Compositions and Associated Methods,” filed on Jul. 14, 2004, which is a continuation-in-part of U.S. application Ser. No. 10/608,748 entitled “Cement Compositions With Improved Fluid Loss Characteristics and Methods of Cementing in Surface and Subterranean Applications,” filed on Jun. 27, 2003.

BACKGROUND

The present invention relates to cementing operations, and more particularly, to cement compositions comprising an improved fluid loss control additive, and methods of using such compositions in surface and subterranean applications.

Hydraulic cement compositions are commonly utilized in subterranean operations, particularly subterranean well completion and remedial operations. For example, hydraulic cement compositions are used in primary cementing operations whereby pipe strings such as casings and liners are cemented in well bores. In performing primary cementing, hydraulic cement compositions are pumped into the annular space between the walls of a well bore and the exterior surface of the pipe string disposed therein. The cement composition is permitted to set in the annular space, thereby forming an annular sheath of hardened substantially impermeable cement therein that substantially supports and positions the pipe string in the well bore and bonds the exterior surface of the pipe string to the walls of the well bore. Hydraulic cement compositions also are used in remedial cementing operations such as plugging highly permeable zones or fractures in well bores, plugging cracks and holes in pipe strings, and the like.

For such well cementing operations to be successful, the cement compositions utilized should include a fluid loss control additive to reduce the loss of fluid, e.g., water, from the cement compositions when they contact permeable subterranean formations and zones. Excessive fluid loss, inter alia, causes a cement composition to be prematurely dehydrated, which limits the amount of cement composition that can be pumped, decreases the compressive strength of the set cement composition, and prevents or reduces bond strength between the set cement composition and the subterranean zone, the walls of pipe, and/or the walls of the well bore. Fluid loss control agents may also be used in surface cement compositions.

Conventional contemporary synthetic fluid loss control additives are large, water-soluble polymers that are capable of functioning at a wider range of temperatures. An example of such synthetic fluid loss control additive is a fluid loss control additive consisting of hydrolyzed copolymers of acrylamide (“AA”) and 2-acrylamido-2-methylpropane sulfonic acid (“AMPS”). However, certain of these AA/AMPS copolymers are useful only in operations where the bottom hole circulating temperature (“BHCT”) ranges from about 90° F. to about 125° F., whereas BHCT ranges encountered in such operations are often outside such a range. Still further, certain of these copolymers have a salt tolerance of only up to about 10%.

The temperature limitations of certain of the AA/AMPS copolymers, e.g., ineffectiveness at temperatures above about 125° F. BHCT, are believed to be the result of hydrolysis of the amide groups. The carboxylate groups formed by such hydrolysis convert the copolymers to materials, which lead to retarding of the setting of the cement and losses in the compressive strength of the set cement. Further, in the lower portion of the above-mentioned temperature range (between about 90° F. to about 100 ° F.), certain of the AA/AMPS copolymers are less effective as a fluid loss control additive, requiring inclusion of larger amounts of the AA/AMPS copolymers than at higher temperatures. The inclusion of a sufficiently large amount of a fluid loss control additive to create a cement composition with acceptable fluid loss often creates viscosity and pumpability problems, since the addition of such copolymer directly affects the resultant slurry rheology. Certain AA/AMPS copolymers exhibit high viscosity and poor mixability, resulting in cement slurries having poor pumpability characteristics during cementing operations. Mixability is a subjective term used to describe how well the components in the cement composition wet and mix with each other, as well as the energy required to create a generally homogeneous slurry.

SUMMARY

The present invention relates to cementing operations, and more particularly, to cement compositions comprising an improved fluid loss control additive, and methods of using such compositions in surface and subterranean applications.

In one embodiment, the present invention provides a cement composition that comprises a cement, water, and a fluid loss control additive, the fluid loss control additive comprising an acrylic acid copolymer derivative, an iron compound, and at least one of a dispersant or a hydratable polymer.

In another embodiment, the present invention provides a fluid loss control additive that comprises an acrylic acid copolymer derivative, an iron compound, and at least one of a dispersant or a hydratable polymer.

In another embodiment, the present invention provides a method of cementing in a subterranean formation that comprises providing a cement composition comprising a cement, water, and a fluid loss control additive, the fluid loss control additive comprising an acrylic acid copolymer derivative, an iron compound, and at least one of a hydratable polymer or a dispersant; placing the cement composition into the subterranean formation; and permitting the cement composition to set therein.

In yet another embodiment, the present invention provides a method of reducing the fluid loss from a cement composition that comprises adding to the cement composition a fluid loss control additive comprising an acrylic acid copolymer derivative, an iron compound, and at least one of a dispersant or a hydratable polymer.

The objects, features and advantages of the present invention will be readily apparent to those skilled in the art upon a reading of the description of the specific embodiments, which follows.

DESCRIPTION

The present invention relates to cementing operations, and more particularly, to cement compositions comprising an improved fluid loss control additive, and methods of using such compositions in surface and subterranean applications. While the compositions and methods of the present invention are useful in a variety of applications, they are particularly useful for subterranean well completion and remedial operations, such as primary cementing, e.g., cementing casings and liners in well bores, including those in production wells, which include multi-lateral subterranean wells. They are also useful for surface cementing operations, including construction cementing operations.

The cement compositions of the present invention generally comprise a cement, water, and a fluid loss control additive of the present invention. A wide variety of optional additives may be included in the cement compositions of the present invention if desired. The cement compositions of the present invention may range in density from about 5 lb/gallon to about 30 lb/gallon. In one embodiment, the cement compositions of the present invention range in density from about 8 lb/gallon to about 20 lb/gallon.

Any cements suitable for use in subterranean applications are suitable for use in the present invention. Furthermore, any cements suitable for use in surface applications, e.g., construction cements, are suitable for use in the present invention. In one embodiment, the improved cement compositions of the present invention comprise a hydraulic cement. A variety of hydraulic cements are suitable for use, including those comprised of calcium, aluminum, silicon, oxygen, and/or sulfur, which set and harden by reaction with water. Such hydraulic cements include, but are not limited to, Portland cements, pozzolanic cements, gypsum cements, high alumina content cements, silica cements, and high alkalinity cements.

The water present in the cement compositions of the present invention may be from any source, provided that it does not contain an excess of compounds that adversely affect other compounds in the cement compositions. For example, a cement composition of the present invention can comprise fresh water, saltwater (e.g., water containing one or more salts dissolved therein), brine (e.g., saturated saltwater), or seawater. The water may be present in an amount sufficient to form a pumpable slurry. Generally, the water is present in the cement compositions of the present invention in an amount in the range of from about 15% to about 200% by weight of cement (“bwoc”) therein. In certain embodiments, the water is present in the cement compositions of the present invention in an amount in the range of from about 25% to about 60% bwoc therein.

The fluid loss control additives of the present invention generally comprise an acrylic acid copolymer derivative, an iron compound, and at least one of a hydratable polymer or a dispersant. Certain embodiments comprise an acrylic acid copolymer derivative, an iron compound, and a hydratable polymer. Certain other embodiments comprise an acrylic acid copolymer derivative, an iron compound, and a dispersant. Optionally, the fluid loss control additives of the present invention may further comprise zeolites, shales, organic acids, deaggregation agents, or combinations thereof.

The fluid loss control additives of the present invention comprise an acrylic acid copolymer derivative. As referred to herein, the term “copolymer” will be understood to mean a polymer comprising two or more different compounds. For example, a “copolymer” may comprise, inter alia, a graft polymer wherein one monomer is grafted onto a backbone comprising another monomer. Any copolymer or copolymer salt of acrylic acid or a derivative thereof will be an “acrylic acid copolymer derivative” as that term is used herein. Examples of suitable acrylic acid derivatives include, but are not limited to, acrylamides, acrylates, acrylonitrile, AMPS, N,N-dimethylacrylamide, N,N-dialkylaminoethylmethacrylate, and acid salts thereof. An example of a suitable acrylic acid copolymer derivative comprises a copolymer, or copolymer salt, comprising first monomers formed from N,N-dimethylacrylamide and second monomers formed from AMPS or derivatives thereof (e.g., acid salts of AMPS). Generally, monomers formed from AMPS or derivatives thereof are represented by formula (1):

wherein M is hydrogen, ammonium, sodium, or potassium.

Another example of a suitable acrylic acid copolymer derivative comprises a graft polymer comprising a backbone comprising at least one of a lignin, a lignite, or their salts, and a grafted pendant group comprising monomers formed from at least one of 2-acrylamido-2-methylpropane sulfonic acid, acrylonitrile, N,N-dimethylacrylamide, acrylic acid, or N,N-dialkylaminoethylmethacrylate. Another example of a suitable acrylic acid copolymer derivative comprises a graft polymer comprising a backbone comprising at least one of derivatized cellulose, polyvinyl alcohol, polyethylene oxide, polypropylene oxide, and a grafted pendant group comprising monomers formed from at least one of AMPS, acrylonitrile, N,N-dimethylacrylamide, acrylic acid, or N,N-dialkylaminoethylmethacrylate. In these embodiments, the alkyl groups in the N,N-dialkylaminoethylmethacrylate may comprise at least one of methyl, ethyl, or propyl radicals. Another example of a suitable acrylic acid copolymer derivative comprises copolymers, or copolymer salts, comprising first monomers formed from AMPS or derivatives thereof, second monomers formed from maleic acid or salts thereof, third monomers formed from N-vinyl caprolactam, and fourth monomers formed from 4-hydroxybutyl vinyl ether. An additional example of a suitable acrylic acid copolymer derivative comprises copolymers, or copolymer salts, comprising first monomers formed from AMPS or derivatives thereof and second monomers formed from hydrolyzed acrylamide. In these embodiments, the acrylamide may be either completely or partially hydrolyzed. Another example of a suitable acrylic acid copolymer derivative comprises copolymers, or copolymer salts, comprising a waffle tannin grafted with at least one backbone having monomers formed from at least one of AMPS or acrylamide grafted thereto. Yet another example of a suitable acrylic acid copolymer derivative comprises a polymer complex comprising 1 part by weight of a polymer comprising 70 mole % of AMPS, 17 mole % of N, N-dimethylacrylamide, and 13 mole % of acrylamide, and 2 parts by weight of hydroxyethylcellulose having 1.5 moles of ethylene oxide substitution. In one embodiment, an acrylic acid copolymer derivative of the present invention comprises a copolymer, or copolymer salt, of a vinylamide morpholine derivative and least one branched N-vinylamide derivative. Generally, the vinylamide morpholine derivatives that may be present in the copolymer, or copolymer salt, are selected from compounds represented by formula (2):

wherein R₁—H or —CH₃ and R₂ is —H, —CH₃, or —CH₂CH₃ and is positioned on any of the four carbon atoms in the morpholine ring. Generally, the N-vinylamide derivatives that may be present in copolymer, or copolymer salt, are selected from the compounds represented by formula (3):

wherein R₃ is R₁—H or —CH₃; R₄ is —H, —CH₃, —CH₂CH₃, —CH(CH₃)₂, —C(CH₃)₃, or —CH(CH₃)₂SO₃X, wherein X is —Na, —NH₄, or —Ca½, and R₅ is —H, —CH₃, or —CH₂CH₃. In one certain embodiment, the vinylamide derivative is acryloylmorpholine and the branched N-vinylamide derivative is the sodium salt of AMPS. In another embodiment, the vinylamide derivative is acryloylmorpholine and a first vinylamide derivative is the sodium salt of AMPS and a second vinylamide derivative is acrylamide.

Generally, the acrylic acid copolymer derivatives included in the fluid loss control additives of the present invention may be manufactured in accordance with any suitable technique for polymer manufacture, such as a variety of techniques for free radical polymerization. Examples of suitable acrylic acid copolymer derivatives are described in U.S. Pat. Nos. 4,015,991; 4,515,635; 4,555,269; 4,676,317; 4,703,801; 5,134,215; 5,147,964; 5,134,215; 5,986,276; 6,085,840; 6,089,318, 6,268,406; 6,715,552; and 6,767,867, the relevant disclosures of which are incorporated herein by reference. Examples of suitable commercially available acrylic acid copolymer derivatives include, inter alia, those commercially available from Halliburton Energy Services, Inc., Duncan, Okla., under the trade names “HALAD®-344”; “HALAD®-413”; “HALAD®-4,” “HALAD®-567” and “HALAD®-700”. In certain embodiments where the acrylic acid copolymer derivative comprises a copolymer or copolymer salt of N,N-dimethylacrylamide and AMPS or derivatives thereof, the copolymer, or copolymer salt, may have a N,N-dimethylacrylamide to AMPS (or derivatives thereof) mole ratio of from about 1:4 to about 4:1. In certain embodiments, the copolymer, or copolymer salt, may have a weight average molecular weight of between about 75,000 daltons and about 300,000 daltons.

Generally, the acrylic acid copolymer derivative may be present in the fluid loss control additives of the present invention in an amount in the range of from about 1% to about 99% by weight. In one embodiment, the acrylic acid copolymer derivative is present in the fluid loss control additive in an amount in the range of from about 30% to about 60% by weight.

Certain embodiments of the fluid loss control additives of the present invention may comprise a dispersant. Where present, the dispersant in the fluid loss control additive acts, inter alia, to control the rheology of the cement composition and to stabilize the cement composition over a broad density range. While a variety of dispersants known to those skilled in the art may be used in accordance with the present invention, one suitable dispersant is a water-soluble polymer prepared by the caustic-catalyzed condensation of formaldehyde with acetone wherein the polymer contains sodium sulfate groups. Such a dispersant is commercially available under the trade designation “CFR-3™” from Halliburton Energy Services, Inc., Duncan, Okla. Another suitable dispersant is a sodium salt of napthalene sulfonic acid, which is commercially available under the trade designation “CFR-2™,” also from Halliburton Energy Services, Inc., Duncan, Okla. Another source of a suitable dispersant is a multi-purpose cement additive commercially available under the trade designation “UNIVERSAL CEMENT SYSTEMS™” from Halliburton Energy Services, Inc., Duncan, Okla.; such additive is disclosed in U.S. Pat. Nos. 5,749,418; 5,968,255; and 5,972,103, the relevant disclosures of which are incorporated herein by reference. Generally, in some embodiments, Universal Cement Systems™ multi-purpose cement additive may comprise in the range of from about 5% to about 70% of a dispersant by weight. Where used, the dispersant is present in the fluid loss control additive of the present invention in an amount sufficient to prevent gelation of the cement composition. In some embodiments, the dispersant is present in the fluid loss control additive of the present invention in an amount in the range of from about 5% to about 70% by weight. In one embodiment, the dispersant is present in the fluid loss control additive of the present invention in an amount in the range of from about 20% to about 40% by weight.

Certain embodiments of the fluid loss control additives of the present invention may comprise a hydratable polymer. Where present, the hydratable polymer in the fluid loss control additive acts, inter alia, to increase the viscosity of the cement composition in which the fluid loss control additive is used. Various hydratable polymers can be utilized in the fluid loss control additive, including, but not limited to, carboxymethylcellulose, hydroxyethylcellulose, carboxymethylhydroxyethylcellulose, vinyl sulfonated polymers, and hydratable graft polymers. An example of a suitable hydratable polymer is a cellulose derivative commercially available from Dow Chemical Co., under the trade name “CARBOTRON 20.” Another source of a suitable hydratable polymer is a multi-purpose cement additive commercially available under the trade dsignation “UNIVERSAL CEMENT SYSTEMS™” from Halliburton Energy Services, Inc., Duncan, Okla.; such additive is disclosed in U.S. Pat. Nos. 5,749,418; 5,968,255; and 5,972,103, the relevant disclosures of which are herein incorporated by reference. Generally, in some embodiments, the Universal Cement Systems™ multi-purpose cement additive may comprise in the range from about 1% to about 20% of a hydratable polymer by weight. Where utilized, the hydratable polymer is present in the fluid loss control additive of the present invention in an amount sufficient to contribute a desired degree of viscosity to the cement composition. Generally, the hydratable polymer is present in the fluid loss control additive of the present invention in an amount in the range of from about 0.1% to about 15% by weight. In one embodiment, the hydratable polymer is present in the fluid loss control additive of the present invention in an amount in the range of from about 1% to about 5% by weight.

Optionally, the fluid loss control additives of the present invention may comprise a zeolite. Where used, the zeolite functions, inter alia, to improve the suspension of the fluid loss control additive in a cement slurry. The zeolite further comprises a mixture of chabazite and amorphous silica. The chabazite is present in the zeolite in an amount in the range of from about 50% by weight to about 75% by weight. In certain embodiments, the chabazite is present in the zeolite in an amount in the range of from about 65% by weight to about 70% by weight. The amorphous silica is generally present in the zeolite in an amount in the range of from about 25% by weight to about 50% by weight. In certain embodiments, the amorphous silica is present in the zeolite in an amount in the range of from about 30% by weight to about 35% by weight. An example of a suitable source of zeolite is available from the C2C Zeolite Corporation of Calgary, Canada. Where used, the zeolite is generally present in the fluid loss control additive of the present invention in an amount in the range of from about 0.1% by weight to about 15% by weight. In certain embodiments, the zeolite is present in the fluid loss control additive of the present invention in an amount in the range of from about 3% by weight to about 7% by weight.

The fluid loss control additives of the present invention also may optionally comprise shale. Where used, the shale functions, inter alia, to improve the ability of the fluid loss control additives of the present invention to flow freely as a powder. A variety of shales are suitable, including those comprised of silicon, aluminum, calcium, and/or magnesium. In some embodiments, the shale comprises vitrified shale. In certain embodiments, the vitrified shale may be fine grain vitrified shale, wherein the fine grain vitrified shale has a particle size distribution in the range of from about 2 micrometers to about 4,750 micrometers. An example of a suitable fine grain vitrified shale is “PRESSURE-SEAL® FINE LCM,” which is commercially available from TXI Energy Services, Inc., Houston, Tex. In another embodiment, the vitrified shale may be coarse grain vitrified shale, wherein the coarse vitrified shale particles may have a particle size distribution in the range of from about 2 micrometers to about 4,750 micrometers. An example of a suitable coarse grain vitrified shale is “PRESSUR-SEAL® COARSE LCM,” which is commercially available from TXI Energy Services, Inc., Houston, Tex. Where used, the shale is generally present in the fluid loss control additive of the present invention of the present invention in an amount in the range of from about 0.1% to about 15% by weight. In certain embodiments, the shale is present in the fluid loss control additive of the present invention in an amount in the range of from about 3% to about 7% by weight.

Optionally, in certain embodiments, the fluid loss control additives of the present invention may comprise iron compounds. Suitable iron compounds include any soluble iron compound that functions, inter alia, in combination with other components that may be present, to aid the cement composition in hydrating in a predictable manner. Among other things, the iron compound may also improve the compressive strength of the cement composition in which it is used. Where used, the iron compound may be, among others, an iron chloride or an iron gluconate. Generally, the iron chloride may be ferrous chloride, ferric chloride, or mixtures thereof. In one embodiment, the iron chloride used in the improved fluid loss control additives of the present invention is anhydrous ferric chloride. An example of a suitable source of anhydrous ferric chloride is commercially available from BASF Corporation in Germany. Another source of a suitable iron chloride is a multi-purpose cement additive commercially available under the trade designation “UNIVERSAL CEMENT SYSTEMS™” from Halliburton Energy Services, Inc., Duncan, Okla.; such additive is disclosed in U.S. Pat. Nos. 5,749,418; 5,968,255; and 5,972,103, the relevant disclosures of which are herein incorporated by reference. Generally, in some embodiments, Universal Cement Systems™ multi-purpose cement additive may comprise in the range of from about 0.5% to about 30% iron chloride by weight. Where used, the iron compound is present in the fluid loss control additive of the present invention in an amount sufficient to allow the cement to be suitable for the subterranean environment of the well being cemented. More particularly, the iron compound may be present in the fluid loss control additive of the present invention of the present invention in an amount in the range of from about 5% to about 25% by weight. In certain embodiments, the iron chloride may be present in the fluid loss control additive of the present invention of the present invention in an amount in the range of from about 10% to about 15% by weight.

In some embodiments, the fluid loss control additive of the present invention may optionally comprise an organic acid. Where present, the organic acid acts, inter alia, to maintain the viscosity of the cement composition in which the fluid loss control additive is used over a broad density range by helping to prevent gelation of the cement composition. Various organic acids can be utilized in the fluid loss control additive, including, but not limited to, tartaric acid, citric acid, gluconic acid, oleic acid, phosphoric acid, and uric acid. An example of a suitable organic acid is commercially available from Halliburton Energy Services, Inc., Duncan, Okla., under the trade name “HR®-25.” A suitable organic acid also may be included in Universal Cement Systems™ multi-purpose cement additive in an amount in the range of from about 0.01% to about 10% by weight. Other examples of suitable organic acids include, for example, organic acids that should have either minimal or no effect on retarding or accelerating the setting of the cement. One of ordinary skill in the art, with the benefit of this disclosure, will recognize the types of organic acids that are appropriate for inclusion in the improved fluid loss control additives of the present invention. Where used, the organic acid is present in the fluid loss control additive of the present invention in an amount sufficient to provide a desired degree of viscosity control. Generally, the organic acid is present in the fluid loss control additive of the present invention in an amount in the range of from about 0.01% to about 5% by weight. In one embodiment, the organic acid is present in the fluid loss control additive of the present invention in an amount in the range of from about 0.01% to about 2% by weight.

Optionally, the fluid loss control additive of the present invention may contain a deaggregation agent. Where used, the deaggregation agent functions, inter alia, to improve the ability of the fluid loss control additive to flow freely as a powder. The deaggregation agent may also contribute a minor source of silica to the multi-purpose cement additive. An example of a suitable deaggregation agent is commercially available from National Pigment and Chemical Co. under the trade name Mica/Brite X150. Alternatively, quartz or ground sand may be used, though the spherical nature of Mica/Brite X150 particles is thought to contribute to improved flow characteristics for the cement composition. A suitable deaggregation agent also may be included in Universal Cement Systems™ multi-purpose cement additive in an amount in the range of from about 1% to about 30% by weight. Generally, the deaggregation agent is present in the fluid loss control additive of the present invention in an amount sufficient to enable the fluid loss control additive of the present invention to flow freely as a powder. In some embodiments, the deaggregation agent is present in the fluid loss control additive of the present invention in an amount in the range of from about 1% to about 15% by weight. In one embodiment, the deaggregation agent is present in the fluid loss control additive of the present invention in an amount in the range of from about 1% to about 10% by weight.

Optionally, the fluid loss control additive of the present invention may comprise a source of silica. Where present in the fluid loss control additive, the silica assists in maintaining the compressive strength of the cement composition after setting. An example of a suitable source of high surface area amorphous silica is commercially available from Halliburton Energy Services, Inc., Duncan, Okla., under the trade name “SILICALITE.” A suitable source of silica also may be included in Universal Cement Systems™ multi-purpose cement additive in an amount in the range of from about 1% to about 50% by weight. Where used, the high surface area amorphous silica is present in the fluid loss control additive of the present invention in an amount sufficient to provide a desired after-set compressive strength. More particularly, the high surface area amorphous silica is present in the fluid loss control additive of the present invention in an amount in the range of from about 0.1% to about 15% by weight. In one embodiment, the high surface area amorphous silica is present in the fluid loss control additive of the present invention in an amount in the range of from about 1% to about 5% by weight.

The improved fluid loss control additives of the present invention may be prepared in a variety of forms, including, inter alia, particulates, solutions, and suspensions. Generally, the fluid loss control additives of the present invention are present in the cement compositions of the present invention in an amount sufficient to provide a desired level of fluid loss control. More particularly, the fluid loss control additive of the present invention may be present in the cement composition in an amount in the range of from about 0.01% to about 10% bwoc. In certain preferred embodiments, the fluid loss control additive of the present invention is present in the cement composition in an amount in the range of from about 0.01% to about 5% bwoc.

As will be recognized by those skilled in the art, the cement compositions of this invention also can include additional suitable additives, including, inter alia, accelerants, set retarders, defoamers, microspheres, fiber, weighting materials, salts, vitrified shale, fly ash, and the like. Any suitable additive may be incorporated within the cement compositions of the present invention. One of ordinary skill in the art, with the benefit of this disclosure, will be able to recognize where a particular additive is suitable for a particular application.

In one embodiment, the present invention provides a cement composition that comprises a cement, water, and a fluid loss control additive, the fluid loss control additive comprising an acrylic acid copolymer derivative; an iron compound; and at least one of a dispersant or a hydratable polymer.

In another embodiment, the present invention provides a fluid loss control additive that comprises an acrylic acid copolymer derivative; an iron compound; and at least one of a dispersant or a hydratable polymer.

In another embodiment, the present invention provides a method of cementing in a subterranean formation that comprises providing a cement composition comprising a cement, water, and a fluid loss control additive, the fluid loss control additive comprising an acrylic acid copolymer derivative, an iron compound, and at least one of a hydratable polymer or a dispersant; placing the cement composition into the subterranean formation; and permitting the cement composition to set therein.

In yet another embodiment, the present invention provides a method of reducing the fluid loss from a cement composition that comprises adding to the cement composition a fluid loss control additive comprising an acrylic acid copolymer derivative; an iron compound; and at least one of a dispersant or a hydratable polymer.

To facilitate a better understanding of the present invention, the following illustrative examples of certain embodiments are given. In no way should such examples be read to limit, or define, the scope of the invention.

EXAMPLE 1

Sample compositions were prepared by mixing a cement slurry with a fluid loss control additive according to the following procedure. Each sample was dry blended, then mixed for 35 seconds at 13,000 rpm in a blender. Next, the sample was conditioned for 20 minutes at 125° F. in an atmospheric consistometer. After the sample was poured into a preheated cell with a 325 mesh screen, a fluid loss test was performed for 30 minutes at 1,000 psi and 125° F., in accordance with API RP 10B, Recommended Practices for Testing Well Cements.

Sample Composition No. 1 (comparative) comprises a 15.6 lb/gallon (“ppg”) slurry of Texas Lehigh Class A cement, with no fluid loss control additives. The fluid loss was found to be 1,574 cubic centimeters.

Sample Composition No. 2 (comparative) was prepared by mixing 0.5% of Universal Cement Systems™ multi-purpose cement additive bwoc with a 15.6 ppg slurry of Texas Lehigh Class A cement. The fluid loss was found to be 1,175 cubic centimeters.

Sample Composition No. 3 (comparative) was prepared by mixing 0.35% of HALAD®-344 bwoc with a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement. The fluid loss was found to be 270 cubic centimeters.

Sample Composition No. 4 was prepared by mixing 0.7% of a fluid loss control additive with a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement. The fluid loss control additive comprised a 1:1 mixture of HALAD®-344 and Universal Cement Systems™ multi-purpose cement additive. Accordingly, Sample Composition No. 4 contained 0.35% HALAD®-344 bwoc and 0.35% Universal Cement Systems™ multi-purpose cement additive bwoc. The fluid loss was found to be 112 cubic centimeters.

Sample Composition No. 5 (comparative) was prepared by mixing 0.5% of HALAD®-344 bwoc with a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement. The fluid loss was found to be 80 cubic centimeters.

A summary of the fluid loss demonstrated by each of the samples is depicted in Table 1, below. TABLE 1 % Universal FLUID Cement % LOSS FLUID Systems ™ HALAD ® -344 (cc) Sample 0 0 1,574 Composition No. 1 Sample 0.5 0 1,175 Composition No. 2 Sample 0 0.35 270 Composition No. 3 Sample 0.35 0.35 112 Composition No. 4 Sample 0 0.5 80 Composition No. 5

Thus, Example 1 demonstrates, inter alia, that the use of a fluid loss control additive comprising a reduced dose of an acrylic acid copolymer derivative delivers performance comparable to a larger dose of an acrylic acid copolymer derivative.

EXAMPLE 2

Sample Composition No. 4 was then permitted to age for a period of two days, and a period of ten days. After each time period had elapsed, a fluid loss test was again performed for 30 minutes at 1,000 psi and 125° F. After aging for a total of two days, Sample Composition No. 4 demonstrated a fluid loss of 84 cubic centimeters. After aging for a total of ten days, Sample Composition No. 4 demonstrated a fluid loss of 76 cubic centimeters. This Example demonstrates, inter alia, that the use of a fluid loss control additive comprising a reduced dose of an acrylic acid copolymer derivative, can deliver performance equal to or superior to a larger dose of an acrylic acid copolymer derivative.

EXAMPLE 3

Sample compositions were prepared by mixing a cement slurry with a fluid loss control additive according to the following procedure. Each sample was dry blended, then mixed for 35 seconds at 13,000 rpm in a blender. Next, the sample was conditioned for 20 minutes at 125° F. in an atmospheric consistometer. After the sample was poured into a preheated cell with a 325 mesh screen, a fluid loss test was performed for 30 minutes at 1,000 psi and 125° F., in accordance with API RP 10B, Recommended Practices for Testing Well Cements.

Sample Composition No. 6 (comparative) was prepared by mixing 0.5% of HALAD®-413 bwoc with a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement. The fluid loss was found to be 615 cubic centimeters.

Sample Composition No. 7 was prepared by mixing a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement with 1.0% of a fluid loss control additive comprising a 1:1 mixture of Universal Cement Systems™ multi-purpose cement additive with HALAD®-413; accordingly, Sample Composition No. 7 contained 0.5% HALAD®-413 bwoc and 0.5% Universal Cement Systems™ multi-purpose cement additive bwoc. The fluid loss was found to be 212 cubic centimeters.

Sample Composition No. 8 (comparative) was prepared by mixing 0.7% of HALAD®-413 bwoc with a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement. The fluid loss was found to be 188 cubic centimeters.

Sample Composition No. 9 (comparative) was prepared by mixing 0.5% of HALAD®-4 bwoc with a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement. The fluid loss was found to be 196 cubic centimeters.

Sample Composition No. 10 was prepared by mixing a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement with 1.0% of a fluid loss control additive comprising a 1:1 mixture of Universal Cement Systems™ multi-purpose cement additive and HALAD®-4; accordingly, Sample Composition No. 10 contained 0.5% HALAD®-4 bwoc and 0.5% Universal Cement Systems™ multi-purpose cement additive bwoc. The fluid loss was found to be 100 cubic centimeters.

Sample Composition No. 11 (comparative) was prepared by mixing 0.7% of HALAD®-4 bwoc with a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement. The fluid loss was found to be 64 cubic centimeters.

A summary of the fluid loss demonstrated by each of the samples is depicted in Table 2, below. TABLE 2 % Universal FLUID Cement % % LOSS FLUID Systems ™ HALAD ® -413 HALAD ® -4 (cc) Sample 0 0.5 0 615 Composition No. 6 Sample 0.5 0.5 0 212 Composition No. 7 Sample 0 0.7 0 188 Composition No. 8 Sample 0 0 0.5 196 Composition No. 9 Sample 0.5 0 0.5 100 Composition No. 10 Sample 0 0 0.7 64 Composition No. 11

Universal Cement Systems™ multi-purpose cement additive comprises a hydratable polymer and a dispersant. Example 3 demonstrates, inter alia, that the use of an improved fluid loss control additive comprising a hydratable polymer, a dispersant, and a reduced dose of an acrylic acid copolymer derivative provides comparable fluid loss control to a fluid loss control additive comprising a larger dose of an acrylic acid copolymer derivative. Inter alia, Example 3 also demonstrates that a variety of an acrylic acid copolymer derivatives are suitable for combination with, inter alia, a hydratable polymer and a dispersant, in the fluid loss control additives of the present invention.

EXAMPLE 4

Sample compositions were prepared by mixing a cement slurry with a fluid loss control additive according to the following procedure. Each sample was dry blended, then mixed for 35 seconds at 13,000 rpm in a blender. Next, the sample was conditioned for 20 minutes at 190° F. in an atmospheric consistometer. After the sample was poured into a preheated cell with a 325 mesh screen, a fluid loss test was performed per API Specification 10.7 for 30 minutes at 1,000 psi and 205° F.

Sample Composition No. 12 (comparative) was prepared by mixing 0.49% of HALAD®-344 bwoc with a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement. The fluid loss at 1,000 psi and 205° F. was found to be 220 cubic centimeters.

Sample Composition No. 13 was prepared by mixing 0.98% of a fluid loss control additive of the present invention with a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement. The fluid loss control additive comprised a 1:1 mixture of Universal Cement Systems™ multi-purpose cement additive and HALAD®-344; accordingly, Sample Composition No. 13 contained 0.49% HALAD®-344 bwoc and 0.49% Universal Cement Systems™ multi-purpose cement additive bwoc. The fluid loss at 1,000 psi and 205° F. was found to be 60 cubic centimeters.

Sample Composition No. 14 (comparative) was prepared by mixing 0.7% of HALAD®-344 bwoc with a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement. The fluid loss at 1,000 psi and 205° F. was found to be 44 cubic centimeters.

A summary of the fluid loss demonstrated by each of the samples is depicted in Table 3, below. TABLE 3 % Universal FLUID Cement % LOSS FLUID Systems ™ HALAD ® -344 (cc) Sample 0 0.49 220 Composition No. 12 Sample 0.49 0.49 60 Composition No. 13 Sample 0 0.7 44 Composition No. 14

Thus, Example 4 demonstrates, inter alia, that the use of a fluid loss control additive comprising a reduced dose of an acrylic acid copolymer derivative delivers performance comparable to a larger dose of an acrylic acid copolymer derivative. Additionally, Example 4 demonstrates that such fluid loss control additive is an effective fluid loss control additive at elevated temperatures and pressures.

EXAMPLE 5

A sample composition was prepared by mixing a cement slurry with a fluid loss control additive according to the following procedure. The sample was dry blended, then mixed for 35 seconds at 13,000 rpm in a blender. Next, the sample was conditioned to 400° F. in 60 minutes in a stirring fluid loss cell. After 60 minutes, a fluid loss test was performed through a 325-mesh screen at 1,000 psi and 400° F. for 30 minutes.

Sample Composition No. 15 was prepared by mixing 0.84% of a fluid loss control additive of the present invention with a 15.6 ppg slurry comprising 30% “SSA-1” bwoc, and the balance comprising an experimental cement bearing compositional similarities to a Class H cement. SSA-1 is a silica flour additive available from Halliburton Energy Services, Inc., of Houston, Tex. The fluid loss control additive comprised a 1:1 mixture of Universal Cement Systems™ multi-purpose cement additive and HALAD®-344; accordingly, Sample Composition No. 15 contained 0.42% HALAD®-344 bwoc and 0.42% Universal Cement Systems™ multi-purpose cement additive bwoc. The fluid loss at 1,000 psi and 400° F. was found to be 400 cubic centimeters.

Among other things, Example 5 demonstrates that the fluid loss control additive of the present invention provides fluid loss control at elevated temperatures.

EXAMPLE 6

The transition time of a cement composition may be defined as the time period starting when the cement composition has sufficient gel strength to support itself yet cannot prevent influx of formation fluids, and ending when the cement composition achieves sufficient gel strength to prevent the influx of such formation fluids. Experimentally, the transition time may be approximated by measuring the time period in which the gel strength of a cement composition progresses from about 100 lb per 100 ft² to about 500 lb per 100 ft².

The zero-gel time, which may also be referred to as the delayed-gel time, refers to the time period starting when the cement composition is placed in a subterranean formation and ending when the gel strength of the cement composition progresses to about 100 lb per 100 ft², i.e., ending when the cement composition begins its transition time.

Sample compositions were prepared by mixing a cement slurry with a fluid loss control additive according to the following procedure. Each sample was dry blended, then mixed for 35 seconds at 13,000 rpm in a blender. Next, the sample was conditioned for 40 minutes to 125° F. in a MiniMac® at 5,000 psi. Then, a static gel strength test was performed.

Sample Composition No. 16 (comparative) was prepared by mixing 0.7% of HALAD®-344 bwoc with a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement. Sample Composition No. 16 demonstrated a zero gel time of 41 minutes, and a transition time of 17 minutes.

Sample Composition No. 17 was prepared by mixing 1.0% of a fluid loss control additive of the present invention with a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement. The fluid loss control additive comprised a 1:1 mixture of Universal Cement Systems™ multi-purpose cement additive and HALAD®-344; accordingly, Sample Composition No. 17 contained 0.5% HALAD®-344 bwoc and 0.5% Universal Cement Systems™ multi-purpose cement additive bwoc. Sample Composition No. 17 demonstrated a zero gel time of 1 hour 16 minutes and a transition time of 17 minutes.

A summary of the data from each of the samples is depicted in Table 4, below. TABLE 4 % Universal Zero Gel Transition Cement % Time (hours: Time FLUID Systems ™ HALAD ® -344 minutes) (minutes) Sample 0 0.7 0:41 17 Composition No. 16 Sample 0.5 0.5 1:16 17 Composition No. 17

Thus, Example 6 demonstrates, inter alia, that the use of a fluid loss control additive comprising a reduced dose of an acrylic acid copolymer derivative delivers performance comparable to a larger dose of the acrylic acid copolymer derivative.

EXAMPLE 7

Sample compositions were prepared by mixing a cement slurry with a fluid loss control additive according to the following procedure. Each sample was dry blended, then mixed for 35 seconds at 13,000 rpm in a blender. Next, the sample was conditioned for 20 minutes at 125° F. in an atmospheric consistometer. After the sample was poured into a preheated cell with a 325 mesh screen, a fluid loss test was performed for 30 minutes at 1,000 psi and 125° F., in accordance with API RP 10B, Recommended Practices for Testing Well Cements.

Sample Composition No. 18 was prepared by mixing 0.7% of a fluid loss control additive of the present invention bwoc with a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement. The fluid loss control additive comprised a 1:1 mixture of Universal Cement Systems™ multi-purpose cement additive with HALAD®-344; accordingly, Sample Composition No. 18 contained 0.35% HALAD®-344 bwoc and 0.35% Universal Cement Systems™ multi-purpose cement additive bwoc. The fluid loss was found to be 80 cubic centimeters.

Sample Composition No. 19 was prepared by mixing a 15.8 ppg slurry of an experimental cement bearing compositional similarities to a Class H cement with 0.7% of a fluid loss control additive comprising 47.5% HALAD®-344 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% zeolite by weight. Accordingly, Sample Composition No. 19 contained 0.3325% HALAD®-344 bwoc, 0.3325% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.035% zeolite bwoc. The fluid loss was found to be 96 cubic centimeters.

Thus, Example 7 demonstrates, inter alia, that the use of a fluid loss control additive of the present invention provides acceptable fluid loss control.

EXAMPLE 8

Sample compositions were prepared by mixing a cement slurry with a fluid loss control additive according to the following procedure. Each sample was dry blended, then mixed for 35 seconds at 13,000 rpm in a blender. Next, the sample was conditioned for 20 minutes at 125° F. in an atmospheric consistometer. After the sample was poured into a preheated cell with a 325 mesh screen, a fluid loss test was performed for 30 minutes at 1,000 psi and 125° F., in accordance with API RP 10B, Recommended Practices for Testing Well Cements.

Sample Composition No. 20 (comparative) comprises a 15.8 ppg slurry of TXI Class H cement, with no fluid loss control additives. The fluid loss was found to be 1,529 cubic centimeters.

Sample Composition No. 21 (comparative) was prepared by mixing 0.35% of Universal Cement Systems™ multi-purpose cement additive bwoc with a 15.8 ppg slurry of TXI Class H cement. The fluid loss was found to be 1,343 cubic centimeters.

Sample Composition No. 22 (comparative) was prepared by mixing 0.35% of HALAD®-344 bwoc with a 15.8 ppg slurry of TXI Class H cement. The fluid loss was found to be 64 cubic centimeters.

Sample Composition No. 23 was prepared by mixing 0.35% of HALAD®-344 bwoc and 0.0157% of a hydrated polymer (CARBOTRON 20) bwoc with a 15.8 ppg slurry of TXI Class H cement. The fluid loss was found to be 60 cubic centimeters.

Sample Composition No. 24 was prepared by mixing 0.35% of HALAD®-344 bwoc, 0.0157% of a hydrated polymer (CARBOTRON 20) bwoc, and 0.204% of a dispersant (CFR-3™) bwoc, with a 15.8 ppg slurry of TXI Class H cement. The fluid loss was found to be 44 cubic centimeters.

Sample Composition No. 25 was prepared by mixing a 15.8 ppg slurry of TXI Class H cement with 0.7% of a fluid loss control additive comprising 47.5% of HALAD®-344 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% zeolite by weight. Accordingly, Sample Composition No. 25 contained 0.3325% HALAD®-344 bwoc, 0.3325% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.035% zeolite bwoc. The fluid loss was found to be 44 cubic centimeters.

Sample Composition No. 26 was prepared by mixing 0.35% of HALAD®-344 bwoc and 0.204% of a dispersant (CFR-3™) bwoc, with a 15.8 ppg slurry of TXI Class H cement. The fluid loss was found to be 48 cubic centimeters.

A summary of the data from each of the samples is depicted in Table 5, below. TABLE 5 % Universal % FLUID Cement % % CARBOTRON % LOSS FLUID Systems ™ HALAD ®-344 Zeolite 20 CFR-3 ™ (cc) Sample 0 0 0 0 0 1,529 Composition No. 20 Sample 0.35 0 0 0 0 1,343 Composition No. 21 Sample 0 0.35 0 0 0 64 Composition No. 22 Sample 0 0.35 0 0.0157 0 60 Composition No. 23 Sample 0 0.35 0 0.0157 0.204 44 Composition No. 24 Sample 0.3325 0.33250 0.035 0 0 44 Composition No. 25 Sample 0 0.35 0 0 0.204 48 Composition No. 26

Among other things, Example 8 demonstrates that the addition of, inter alia, a zeolite, a hydratable polymer, and a dispersant, to an acrylic acid copolymer derivative provides improved fluid loss control.

EXAMPLE 9

Sample compositions were prepared by mixing a cement slurry with a fluid loss control additive according to the following procedure. Each sample was dry blended, then mixed for 35 seconds at 13,000 rpm in a blender. Next, the sample was conditioned for 20 minutes at 125° F. in an atmospheric consistometer. After the sample was poured into a preheated cell with a 325 mesh screen, a fluid loss test was performed for 30 minutes at 1,000 psi and 125° F., in accordance with API RP 10B, Recommended Practices for Testing Well Cements.

Sample Composition No. 27 (comparative) was prepared by mixing 0.7% of HALAD®-413 bwoc with a 16.4 ppg slurry of Capitol Class H cement. The fluid loss was found to be 44 cubic centimeters.

Sample Composition No. 28 (comparative) was prepared by mixing 0.475% of HALAD®-413 bwoc with a 16.4 ppg slurry of Capitol Class H cement. The fluid loss was found to be 115 cubic centimeters.

Sample Composition No. 29 was prepared by mixing 1.0% of a fluid loss control additive of the present invention bwoc with a 16.4 ppg slurry of Capitol Class H cement. The fluid loss control additive comprised 47.5% HALAD®-413 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% zeolite by weight. Accordingly, Sample Composition No. 29 comprises 0.475% HALAD®-413 bwoc, 0.475% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.05% zeolite bwoc. The fluid loss was found to be 60 cubic centimeters.

Sample Composition No. 30 was prepared by mixing 1.0% of a fluid loss control additive of the present invention bwoc with a 16.4 ppg slurry of Capitol Class H cement. The fluid loss control additive comprised 47.5% HALAD®-413 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% shale by weight. Accordingly, Sample Composition No. 30 comprises 0.475% HALAD®-413 bwoc, 0.475% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.05% shale bwoc. The fluid loss was found to be 72 cubic centimeters.

Sample Composition No. 31 was prepared by mixing 1.0% of a fluid loss control additive bwoc with a 16.4 ppg slurry of Capitol Class H cement. The fluid loss control additive comprised 47.5% HALAD®-413 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% vitrified by weight. Accordingly, Sample Composition No. 31 comprises 0.475% HALAD®-413 bwoc, 0.475% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.05% vitrified bwoc. The fluid loss was found to be 62 cubic centimeters.

A summary of the data from each sample is depicted in Table 6, below. TABLE 6 % Universal % FLUID Cement % % % Vitrified LOSS FLUID Systems ™ HALAD ®-413 Zeolite Shale Shale (cc) Sample 0 0.7 0 0 0 44 Composition No. 27 Sample 0 0.475 0 0 0 115 Composition No. 28 Sample 0.475 0.475 0.05 0 0 60 Composition No. 29 Sample 0.475 0.475 0 0.05 0 72 Composition No. 30 Sample 0.475 0.475 0 0 0.05 62 Composition No. 31

Thus, Example 9 demonstrates, inter alia, that the use of a fluid loss control additive comprising a reduced dose of an acrylic acid copolymer derivative delivers performance comparable to a larger dose of the acrylic acid copolymer derivative.

EXAMPLE 10

Sample compositions were prepared by mixing a cement slurry with a fluid loss control additive according to the following procedure. Each sample was dry blended, then mixed for 35 seconds at 13,000 rpm in a blender. Next, the sample was conditioned for 20 minutes at 180° F. in an atmospheric consistometer. After the sample was poured into a preheated cell with a 325 mesh screen, a fluid loss test was performed for 30 minutes at 1,000 psi and 180° F., in accordance with API RP 10B, Recommended Practices for Testing Well Cements.

Sample Composition No. 32 (comparative) was prepared by mixing 2% of HALAD®-413 bwoc with a 17.7 ppg slurry that comprised Capitol Class H cement, 35% SSA-1 bwoc, 17.5% sodium chloride bwoc, 16% of a weighting material bwoc, and 0.25% of a set retarder (HR®-5) bwoc. HR®-5 retarder is a cement set retarder that is commercially available from Halliburton Energy Services, Duncan, Okla. The fluid loss was found to be 26 cubic centimeters.

Sample Composition No. 33 was prepared by mixing 2% of a fluid loss control additive of the present invention bwoc with a 17.7 ppg slurry that comprised Capitol Class H cement, 35% SSA-1 bwoc, 37.2% salt by weight of water, 16% of a weighting material bwoc, and 0.25% of a set retarder (HR®-5) bwoc. The fluid loss control additive comprised 47.5% HALAD®-413 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% zeolite by weight. Accordingly, Sample Composition No. 33 comprised 0.95% HALAD®-413 bwoc, 0.95% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.1% zeolite bwoc. The fluid loss was found to be 82 cubic centimeters.

Sample Composition No. 34 was prepared by mixing 3% of a fluid loss control additive of the present invention bwoc with a 17.7 ppg slurry that comprised Capitol Class H cement, 35% SSA-1 bwoc, 37.2% salt by weight of water, 16% of a weighting material bwoc, and 0.25% of a set retarder (HR®-5) bwoc. The fluid loss control additive comprised 47.5% HALAD®-413 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% zeolite by weight. Accordingly, Sample Composition No. 34 comprised 1.425% HALAD®-413 bwoc, 1.425% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.15% zeolite bwoc. The fluid loss was found to be 33 cubic centimeters.

Sample Composition No. 35 was prepared by mixing 3% of a fluid loss control additive of the present invention bwoc with a 17.7 ppg slurry that comprised Capitol Class H cement, 35% SSA-1 bwoc, 37.2% salt by weight of water, 16% of a weighting material bwoc, and 0.25% of a set retarder (HR®-5) bwoc. The fluid loss control additive comprised 47.5% HALAD®-413 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% shale by weight. Accordingly, Sample Composition No. 35 comprised 1.425% HALAD®-413 bwoc, 1.425% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.15% shale bwoc. The fluid loss was found to be 20 cubic centimeters.

Sample Composition No. 36 was prepared by mixing 3% of a fluid loss control additive of the present invention bwoc with a 17.7 ppg slurry that comprised Capitol Class H cement, 35% SSA-1 bwoc, 37.2% salt by weight of water, 16% of a weighting material bwoc, and 0.25% of a set retarder (HR®-5) bwoc. The fluid loss control additive comprised 47.5% HALAD®-413 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% vitrified shale by weight. Accordingly, Sample Composition No. 36 comprised 1.425% HALAD®-413 bwoc, 1.425% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.15% vitrified shale bwoc. The fluid loss was found to be 18 cubic centimeters.

A summary of the data for each of these samples is provided below in Table 7. TABLE 7 % Universal % FLUID Cement % % % Vitrified LOSS FLUID Systems ™ HALAD ®-413 Zeolite Shale Shale (cc) Sample 0 2.0 0 0 0 26 Composition No. 32 Sample 0.95 0.95 0.1 0 0 82 Composition No. 33 Sample 1.425 1.425 0.15 0 0 33 Composition No. 34 Sample 1.425 1.425 0 0.15 0 20 Composition No. 35 Sample 1.425 1.425 0 0 0.15 18 Composition No. 36

Among other things, Example 10 demonstrates that the use of a fluid loss control additive comprising a reduced dose of an acrylic acid copolymer derivative delivers performance comparable to a larger dose of the acrylic acid copolymer derivative.

EXAMPLE 11

Sample compositions were prepared by mixing a cement slurry with a fluid loss control additive according to the following procedure. Each sample was dry blended, then mixed for 35 seconds at 13,000 rpm in a blender. Next, the sample was conditioned for 20 minutes at 125° F. in an atmospheric consistometer. After the sample was poured into a preheated cell with a 325 mesh screen, a fluid loss test was performed for 30 minutes at 1,000 psi and 125° F., in accordance with API RP 10B, Recommended Practices for Testing Well Cements.

Sample Composition No. 37 (comparative) was prepared by mixing 0.6% bwoc of an acrylic acid copolymer derivative with a 16.4 ppg slurry that comprised Lehigh Class H cement. The acrylic acid copolymer derivative comprised a polymer complex comprising 1 part by weight of a polymer comprising 70 mole % of AMPS, 17 mole % of N, N-dimethylacrylamide, and 13 mole % of acrylamide, and 2 parts by weight of hydroxyethylcellulose having 1.5 moles of ethylene oxide substitution. The fluid loss was found to be 242 cubic centimeters.

Sample Composition No. 38 was prepared by mixing 0.8% of a fluid loss control additive of the present invention bwoc with a 16.4 ppg slurry that comprised Lehigh Class H cement. The fluid loss control additive comprised a 1:1 mixture of an acrylic acid copolymer derivative and Universal Cement Systems™ multi-purpose cement additive. The acrylic acid copolymer derivative comprised a polymer complex comprising 1 part by weight of a polymer comprising 70 mole % of AMPS, 17 mole % of N, N-dimethylacrylamide, and 13 mole % of acrylamide, and 2 parts by weight of hydroxyethylcellulose having 1.5 moles of ethylene oxide substitution. Accordingly, Sample Composition No. 38 comprised 0.4% of the first acrylic acid copolymer derivative bwoc and 0.4% Universal Cement Systems™ multi-purpose cement additive bwoc. The fluid loss was found to be 312 cubic centimeters.

Sample Composition No. 39 (comparative) was prepared by mixing 0.6% of an acrylic acid copolymer derivative bwoc with a 16.4 ppg slurry that comprised Lehigh Class H cement. The acrylic acid copolymer derivative comprised first monomers formed from AMPS, second monomers formed from maleic acid, third monomers formed from N-vinyl caprolactam, and fourth monomers formed from 4-hydroxybutyl vinyl ether. The fluid loss was found to be 64 cubic centimeters.

Sample Composition No. 40 was prepared by mixing 0.8% of a fluid loss control additive of the present invention bwoc with a 16.4 ppg slurry that comprised Lehigh Class H cement. The fluid loss control additive comprised a 1:1 mixture of an acrylic acid copolymer derivative and Universal Cement Systems™ multi-purpose cement additive. The acrylic acid copolymer derivative comprised first monomers formed from AMPS, second monomers formed from maleic acid, third monomers formed from N-vinyl caprolactam, and fourth monomers formed from 4-hydroxybutyl vinyl ether. Accordingly, Sample Composition No. 38 comprised 0.4% of the acrylic acid copolymer derivative bwoc and 0.4% Universal Cement Systems™ multi-purpose cement additive bwoc. The fluid loss was found to be 64 cubic centimeters.

Sample Composition No. 41 (comparative) was prepared by mixing 0.6% of an acrylic acid copolymer derivative (22% active) bwoc with a 16.4 ppg slurry that comprised Lehigh Class H cement. The acrylic acid copolymer derivative comprised a waffle tannin having monomers formed from AMPS grafted thereto. The fluid loss was found to be 30 cubic centimeters.

Sample Composition No. 42 was prepared by mixing 0.8% of a fluid loss control additive of the present invention bwoc with a 16.4 ppg slurry that comprised Lehigh Class H cement. The fluid loss control additive comprised a 1:1 mixture of an acrylic acid copolymer derivative and Universal Cement Systems™ multi-purpose cement additive. The acrylic acid copolymer derivative comprised a waffle tannin having monomers formed from AMPS grafted thereto. Accordingly, Sample Composition No. 42 comprised 0.4% the acrylic acid copolymer derivative bwoc and 0.4% Universal Cement Systems™ multi-purpose cement additive bwoc. The fluid loss was found to be 28 cubic centimeters.

A summary of the data for each of these samples is provided below in Table 8. TABLE 8 % Universal % Acrylic Acid FLUID Cement Copolymer LOSS FLUID Systems ™ Derivative (cc) Sample 0 0.6¹ 242 Composition No. 37 Sample 0.4 0.4¹ 312 Composition No. 38 Sample 0 0.6² 64 Composition No. 39 Sample 0.4 0.4² 64 Composition No. 40 Sample 0 0.6³ 30 Composition No. 41 Sample 0.4 0.4³ 28 Composition No. 42 ¹The acrylic acid copolymer derivative comprised a polymer complex comprising 1 part by weight of a polymer comprising 70 mole % of AMPS, 17 mole % of N,N-dimethylacrylamide, and 13 mole % of acrylamide, and 2 parts by weight of hydroxyethylcellulose having 1.5 moles of ethylene oxide substitution. ²The acrylic acid copolymer derivative comprised first monomers formed from AMPS, second monomers formed from maleic acid, third monomers formed from N-vinyl caprolactam, and fourth monomers formed from 4-hydroxybutyl vinyl ether. ³The acrylic acid copolymer derivative comprised a waffle tannin having monomers formed from AMPS grafted thereto.

Thus, Example 11 demonstrates, among other things, that the use of a fluid loss control additive comprising a reduced dose of an acrylic acid copolymer derivative delivers performance comparable to a larger dose of the acrylic acid copolymer derivative.

EXAMPLE 12

Sample compositions were prepared according to the following procedure. Each sample was dry blended, then mixed for 35 seconds at 13,000 rpm in a blender. After sample preparation, compressive strength tests were performed on each of the samples using an ultrasonic cement analyzer according to API Specification 10A, Twenty-Third Edition, April 2002. Furthermore, the time for each of the samples to reach a compressive strength of 50 psi and 500 psi, respectively, was recorded. Each sample was brought up to 220° F. and 3,000 psi in 60 minutes. Next, the samples were brought up to 250° F. in 240 minutes while static.

Sample Composition No. 43 (comparative) was prepared by mixing 0.5% of HALAD®-413 bwoc with a 16.9 ppg slurry that comprised Texas Lehigh Class H cement, 35% SSA-1 bwoc and 0.7% of a set retarder (HR®-601). HR-601® retarder is a set retarder that is commercially available from Halliburton Energy Services, Duncan, Okla.

Sample Composition No. 44 was prepared by mixing 0.73% of a fluid loss control additive of the present invention bwoc with a 16.9 ppg slurry that comprised Texas Lehigh Class H cement, 35% SSA-1 bwoc and 0.7% of a set retarder (HR®-601). The fluid loss control additive comprised 47.5% HALAD®-413 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% zeolite by weight. Accordingly, Sample Composition No. 44 comprised 0.347% HALAD®-413 bwoc, 0.347% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.036% zeolite bwoc.

Sample Composition No. 45 was prepared by mixing 0.73% of a fluid loss control additive of the present invention bwoc with a 16.9 ppg slurry that comprised Texas Lehigh Class H cement, 35% SSA-1 bwoc and 0.7% of a set retarder (HR®-601). The fluid loss control additive comprised 47.5% HALAD®-413 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% shale by weight. Accordingly, Sample Composition No. 45 comprised 0.347% HALAD®-413 bwoc, 0.347% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.036% shale bwoc.

Sample Composition No. 46 was prepared by mixing 0.73% of a fluid loss control additive of the present invention bwoc with a 16.9 ppg slurry that comprised Texas Lehigh Class H cement, 35% SSA-1 bwoc and 0.7% of a set retarder (HR®-601). The fluid loss control additive comprised 47.5% HALAD®-413 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% vitrified shale by weight. Accordingly, Sample Composition No. 46 comprised 0.347% HALAD®-413 bwoc, 0.347% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.036% vitrified shale bwoc.

A summary of the data for each of these samples is provided below in Table 9. TABLE 9 Time for Time for 50 psi 500 psi 12 Hour 24 Hour Compressive Compressive Compressive Compressive Strength Strength Strength Strength at 250° F. at 250° F. at 250° F. at 250° F. (hr:min) (hr:min) (psi) (psi) Sample 3:45 4:13 2,834 4,309 Composition No. 43 Sample 4:05 4:47 2,926 4,143 Composition No. 44 Sample 5:28 6:02 2,604 4,135 Composition No. 45 Sample 3:32 4:04 3,234 4,653 Composition No. 46

Thus, Example 12 demonstrates, inter alia, that cement compositions of the present invention may provide acceptable levels of compressive strength.

EXAMPLE 13

Sample compositions were prepared by mixing a cement slurry with a fluid loss control additive according to the following procedure. Each sample was dry blended, then mixed for 35 seconds at 13,000 rpm in a blender. After preparation, the sample was poured into a stirring fluid cell with a 325 mesh screen and brought up to 325° F. in about 1.5 hours. Next, a fluid loss test was performed for 30 minutes at 1,000 psi and 325° F., in accordance with API RP 10B, Recommended Practices for Testing Well Cements.

Sample Composition No. 47 (comparative) was prepared by mixing 2% of HALAD®-413 bwoc with a 18.5 ppg slurry that comprised Texas Lehigh Class H cement, 35% SSA-1 bwoc, 17.4% Sodium Chloride bwoc, 32% of a weighting material bwoc, 0.3% of SUSPEND™ HT bwoc, 1% of a set retarder (HR®-12), and 0.5% of a set retarder (HR®-25). HR®-12 retarder and HR®-25 retarder are cement set retarders that are commercially available from Halliburton Energy Services, Duncan, Okla. SUSPEND™ HT is a high temperature suspension agent that is commercially available from Halliburton Energy Services, Duncan, Okla.

Sample Composition No. 48 was prepared by mixing 2.92% of a fluid loss control additive of the present invention bwoc with a 18.5 ppg slurry that comprised Texas Lehigh Class H cement, 35% SSA-1 bwoc, 17.4% Sodium Chloride bwoc, 32% of a weighting material bwoc, 0.3% of SUSPEND™ HT bwoc, 1% of a set retarder (HR®-12), and 0.5% of a set retarder (HR®-25). The fluid loss control additive comprised 47.5% of HALAD®-413 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% zeolite by weight. Accordingly, Sample Composition No. 48 comprised 1.39% HALAD®-413 bwoc, 1.39% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.15% zeolite bwoc.

Sample Composition No. 49 was prepared by mixing 2.92% of a fluid loss control additive of the present invention bwoc with a 18.5 ppg slurry that comprised Texas Lehigh Class H cement, 35% SSA-1 bwoc, 17.4% Sodium Chloride bwoc, 32% of a weighting material bwoc, 0.3% SUSPEND™ HT bwoc, 1% of a set retarder (HR®-12), and 0.5% of a set retarder (HR®-25). The fluid loss control additive comprised 47.5% HALAD®-413 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% shale by weight. Accordingly, Sample Composition No. 49 comprised 1.39% HALAD®-413 bwoc, 1.39% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.15% shale bwoc.

Sample Composition No. 50 was prepared by mixing 2.92% of a fluid loss control additive of the present invention bwoc with a 18.5 ppg slurry that comprised Texas Lehigh Class H cement, 35% SSA-1 bwoc, 17.4% Sodium Chloride bwoc, 32% of a weighting material bwoc, 0.3% SUSPEND™ HT bwoc, 1% of a set retarder (HR®-12), and 0.5% of a set retarder (HR®-25). The fluid loss control additive comprised 47.5% HALAD®-413 by weight, 47.5% Universal Cement Systems™ multi-purpose cement additive by weight, and 5% vitrified shale by weight. Accordingly, Sample Composition No. 50 comprised 1.39% HALAD®-413 bwoc, 1.39% Universal Cement Systems™ multi-purpose cement additive bwoc, and 0.15% vitrified shale bwoc.

A summary of the data for each of these samples is provided below in Table 10. TABLE 10 % Universal % FLUID Cement % % % Vitrified LOSS Systems ™ HALAD ®-413 Zeolite Shale Shale (cc) Sample 0 2 0 0 0 41 Composition No. 47 Sample 1.39 1.39 0.15 0 0 52 Composition No. 48 Sample 1.39 1.39 0 0.15 0 60 Composition No. 49 Sample 1.39 1.39 0 0 0.15 55 Composition No. 50

Thus, Example 13 demonstrates, among other things, that the use of a fluid loss control additive comprising a reduced dose of an acrylic acid copolymer derivative delivers performance comparable to a larger dose of the acrylic acid copolymer derivative.

Therefore, the present invention is well adapted to carry out the objects and attain the ends and advantages mentioned as well as those that are inherent therein. While numerous changes may be made by those skilled in the art, such changes are encompassed within the spirit of this invention as defined by the appended claims. 

1. A method of cementing in a subterranean formation comprising: providing a cement composition comprising a cement, water, and a fluid loss control additive, the fluid loss control additive comprising: an acrylic acid copolymer derivative, an iron compound, and at least one of a hydratable polymer or a dispersant; placing the cement composition into the subterranean formation; and permitting the cement composition to set therein.
 2. The method of claim 1 wherein the acrylic acid copolymer derivative comprises a copolymer or a copolymer salt that comprises first monomers formed from N,N-dimethylacrylamide, and second monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof.
 3. The method of claim 2 wherein the copolymer or the copolymer salt has a N,N-dimethylacrylamide to 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof mole ratio of from about 1:4 to about 4:1.
 4. The method of claim 2 wherein the copolymer or the copolymer salt has a weight average molecular weight of between about 75,000 daltons and about 300,000 daltons.
 5. The method of claim 1 wherein the acrylic acid copolymer derivative comprises a graft polymer comprising a backbone comprising at least one of a lignin, a lignite, or their salts and a grafted pendant group comprising monomers formed from at least one of 2-acrylamido-2-methylpropane sulfonic acid, acrylonitrile, N,N-dimethylacrylamide, acrylic acid, or N,N-dialkylaminoethylmethacrylate.
 6. The method of claim 1 wherein the acrylic acid copolymer derivative comprises a graft polymer comprising a backbone comprising at least one of derivatized cellulose, polyvinyl alcohol, polyethylene oxide, or polypropylene oxide, and a grafted pendant group comprising monomers formed from at least one of 2-acrylamido-2-methylpropane sulfonic acid, acrylonitrile, N,N-dimethylacrylamide, acrylic acid, or N,N-dialkylaminoethylmethacrylate.
 7. The method of claim 1 wherein the acrylic acid copolymer derivative comprises a copolymer or a copolymer salt comprising first monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof.
 8. The method of claim 7 wherein the copolymer or the copolymer salt comprises first monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof, second monomers formed from maleic acid or a salt thereof, third monomers formed from N-vinyl caprolactam, and fourth monomers formed from 4-hydroxybutyl vinyl ether.
 9. The method of claim 7 wherein the copolymer or the copolymer salt comprises a copolymer comprising first monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof, and second monomers formed from hydrolyzed acrylamide.
 10. The method of claim 1 wherein the acrylic acid copolymer derivative comprises a copolymer or copolymer salt comprising a waffle tannin having monomers formed from at least one of 2-acrylamido-2-methylpropane sulfonic acid or acrylamide grafted thereto.
 11. The method of claim 1 wherein the acrylic acid copolymer derivative comprises 1 part by weight of a polymer comprising 70 mole % of AMPS, 17 mole % of N, N-dimethylacrylamide, and 13 mole % of acrylamide, and 2 parts by weight of hydroxyethylcellulose having 1.5 moles of ethylene oxide substitution.
 12. The method of claim 1 wherein the acrylic acid copolymer derivative comprises a copolymer or copolymer salt of a vinylamide morpholine derivative and least one branched N-vinylamide derivative, wherein the vinylamide morpholine derivative is selected from compounds represented by the formula:

wherein R₁—H or —CH₃ and R₂ is —H, —CH₃, or —CH₂CH₃ and is positioned on any of the four carbon atoms in the morpholine ring, and the N-vinylamide derivative is selected from the compounds represented by the formula:

wherein R₃ is R₁—H or —CH₃; R₄ is —H, —CH₃, —CH₂CH₃, —CH(CH₃)₂, —C(CH₃)₃, or —CH(CH₃)₂SO₃X, wherein X is —Na, —NH₄, or —Ca½, and R₅ is —H, —CH₃, or —CH₂CH₃.
 13. The method of claim 12 wherein the vinylamide derivative is acryloylmorpholine, and the branched N-vinylamide derivative is a sodium salt of 2-acrylamido-2-methylpropanesulfonic acid.
 14. The method of claim 12 wherein the vinylamide derivative is acryloylmorpholine, a first vinylamide derivative is a sodium salt of 2-acrylamido-2-methylpropanesulfonic acid, and a second vinylamide derivative is acrylamide.
 15. The method of claim 1 wherein the hydratable polymer comprises carboxymethylcellulose, hydroxyethylcellulose, carboxymethylhydroxyethylcellulose, a vinyl sulfonated polymer, a hydratable graft polymer, or a mixture thereof.
 16. The method of claim 1 wherein the hydratable polymer is present in the fluid loss control additive in an amount in the range of from about 0.1% to about 15% by weight of the fluid loss control additive.
 17. The method of claim 1 wherein the dispersant comprises a sodium salt of napthalene sulfonic acid, or a water-soluble polymer prepared by the caustic-catalyzed condensation of formaldehyde with acetone wherein the polymer contains sodium sulfate groups.
 18. The method of claim 1 wherein the dispersant is present in the fluid loss control additive in an amount sufficient to prevent gelation of the cement composition.
 19. The method of claim 1 wherein the dispersant is present in the fluid loss control additive in an amount in the range of from about 5% to about 70% by weight of the fluid loss control additive.
 20. The method of claim 1 wherein the iron compound is present in the fluid loss control additive in an amount in the range of from about 5% to about 25% by weight of the fluid loss control additive.
 21. The method of claim 1 wherein the iron compound is present in the fluid loss control additive in an amount in the range of from about 10% to about 15% by weight of the fluid loss control additive.
 22. The method of claim 1 wherein the iron compound is an iron chloride or an iron gluconate.
 23. The method of claim 22 wherein the iron chloride is ferrous chloride, ferric chloride, or a mixture thereof.
 24. The method of claim 1 wherein the fluid loss control additive further comprises a zeolite.
 25. The method of claim 24 wherein the zeolite further comprises chabazite and amorphous silica.
 26. The method of claim 24 wherein the zeolite is present in the fluid loss control additive in an amount in the range of from about 0.1% to about 15% by weight of the fluid loss control additive.
 27. The method of claim 24 wherein the fluid loss control additive further comprises an organic acid, a deaggregation agent, silica, or a combination thereof.
 28. The method of claim 1 wherein the fluid loss control additive further comprises a shale.
 29. The method of claim 28 wherein the shale comprises vitrified shale.
 30. The method of claim 28 wherein the shale is present in the fluid loss control additive in an amount in the range of from about 0.1% to about 15% by weight of the fluid loss control additive.
 31. The method of claim 28 wherein the fluid loss control additive further comprises an organic acid, a deaggregation agent, silica, or a combination thereof.
 32. The method of claim 31 wherein the organic acid is present in the fluid loss control additive in an amount sufficient to provide a desired degree of viscosity control.
 33. The method of claim 31 wherein the organic acid is present in the fluid loss control additive in an amount in the range of from about 0.01% to about 5% by weight of the fluid loss control additive.
 34. The method of claim 31 wherein the deaggregation agent is present in the fluid loss control additive in an amount sufficient to enable the fluid loss control additive to flow freely as a powder.
 35. The method of claim 31 wherein the deaggregation agent is present in the fluid loss control additive in an amount in the range of from about 1% to about 15% by weight of the fluid loss control additive.
 36. The method of claim 31 wherein the silica is high surface area amorphous silica.
 37. The method of claim 36 wherein the high surface area amorphous silica is present in the fluid loss control additive in an amount sufficient to provide a desired after-set compressive strength.
 38. The method of claim 36 wherein the high surface area amorphous silica is present in the fluid loss control additive in an amount in the range of from about 0.1% to about 15% by weight of the fluid loss control additive.
 39. The method of claim 1 wherein the cement comprises a Portland cement, a pozzolanic cement, a gypsum cement, a high alumina content cement, a silica cement, or a high alkalinity cement.
 40. The method of claim 1 wherein the water is present in the cement composition in an amount sufficient to form a pumpable slurry.
 41. The method of claim 1 wherein the water is present in the cement composition in an amount in the range of from about 15% to about 200% by weight of cement.
 42. The method of claim 1 wherein the cement composition has a density in the range of from about 5 pounds per gallon to about 30 pounds per gallon.
 43. The method of claim 1 wherein the fluid loss control additive is present in the cement composition in an amount sufficient to provide a desired degree of fluid loss control.
 44. The method of claim 1 wherein the fluid loss control additive is present in the cement composition in an amount in the range of from about 0.01% to about 5% by weight of cement.
 45. The method of claim 1 wherein the acrylic acid copolymer derivative is present in the fluid loss control additive in an amount in the range of from about 1% to about 99% by weight.
 46. The method of claim 1 wherein the fluid loss control additive is present in the cement composition in an amount in the range of from about 0.01% to about 5% by weight of cement, the iron compound is present in the fluid loss control additive in an amount in the range of from about 10% to about 15% by weight of the fluid loss control additive, the hydratable polymer is present in the fluid loss control additive in an amount in the range of from about 1% to about 5% by weight of the fluid loss control additive, and the dispersant is present in the fluid loss control additive in an amount in the range of from about 20% to about 45% by weight of the fluid loss control additive.
 47. A method of reducing the fluid loss from a cement composition, comprising adding to the cement composition a fluid loss control additive comprising: an acrylic acid copolymer derivative, an iron compound, and at least one of a dispersant or a hydratable polymer.
 48. The method of claim 47 wherein the acrylic acid copolymer derivative comprises a copolymer or a copolymer salt that comprises first monomers formed from N,N-dimethylacrylamide, and second monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof.
 49. The method of claim 48 wherein the copolymer or the copolymer salt has a N,N-dimethylacrylamide to 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof mole ratio of from about 1:4 to about 4:1.
 50. The method of claim 48 wherein the copolymer or the copolymer salt has a weight average molecular weight of between about 75,000 daltons and about 300,000 daltons.
 51. The method of claim 47 wherein the acrylic acid copolymer derivative comprises a graft polymer comprising a backbone comprising at least one of a lignin, a lignite, or their salts and a grafted pendant group comprising monomers formed from at least one of 2-acrylamido-2-methylpropane sulfonic acid, acrylonitrile, N,N-dimethylacrylamide, acrylic acid, or N,N-dialkylaminoethylmethacrylate.
 52. The method of claim 47 wherein the acrylic acid copolymer derivative comprises a graft polymer comprising a backbone comprising at least one of derivatized cellulose, polyvinyl alcohol, polyethylene oxide, or polypropylene oxide, and a grafted pendant group comprising monomers formed from at least one of 2-acrylamido-2-methylpropane sulfonic acid, acrylonitrile, N,N-dimethylacrylamide, acrylic acid, or N,N-dialkylaminoethylmethacrylate.
 53. The method of claim 47 wherein the acrylic acid copolymer derivative comprises a copolymer or a copolymer salt comprising first monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof.
 54. The method of claim 53 wherein the copolymer or the copolymer salt comprises first monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof, second monomers formed from maleic acid or a salt thereof, third monomers formed from N-vinyl caprolactam, and fourth monomers formed from 4-hydroxybutyl vinyl ether.
 55. The method of claim 53 wherein the copolymer or the copolymer salt comprises a copolymer comprising first monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof, and second monomers formed from hydrolyzed acrylamide.
 56. The method of claim 47 wherein the acrylic acid copolymer derivative comprises a copolymer or copolymer salt comprising a waffle tannin having monomers formed from at least one of 2-acrylamido-2-methylpropane sulfonic acid or acrylamide grafted thereto.
 57. The method of claim 47 wherein the acrylic acid copolymer derivative comprises 1 part by weight of a polymer comprising 70 mole % of AMPS, 17 mole % of N, N-dimethylacrylamide, and 13 mole % of acrylamide, and 2 parts by weight of hydroxyethylcellulose having 1.5 moles of ethylene oxide substitution.
 58. The method of claim 47 wherein the acrylic acid copolymer derivative comprises a copolymer or copolymer salt of a vinylamide morpholine derivative and least one branched N-vinylamide derivative, wherein the vinylamide morpholine derivative is selected from compounds represented by the formula:

wherein R₁—H or —CH₃ and R₂ is —H, —CH₃, or —CH₂CH₃ and is positioned on any of the four carbon atoms in the morpholine ring, and the N-vinylamide derivative is selected from the compounds represented by the formula:

wherein R₃ is R₁—H or —CH₃; R₄ is —H, —CH₃, —CH₂CH₃, —CH(CH₃)₂, —C(CH₃)₃, or —CH(CH₃)₂SO₃X, wherein X is —Na, —NH₄, or —Ca½, and R₅ is —H, —CH₃, or —CH₂CH₃.
 59. The method of claim 58 wherein the vinylamide derivative is acryloylmorpholine and the branched N-vinylamide derivative is a sodium salt of b 2-acrylamido-2-methylpropanesulfonic acid.
 60. The method of claim 58 wherein the vinylamide derivative is acryloylmorpholine, a first vinylamide derivative is a sodium salt of 2-acrylamido-2-methylpropanesulfonic acid, and a second vinylamide derivative is acrylamide.
 61. The method of claim 47 wherein the hydratable polymer comprises carboxymethylcellulose, hydroxyethylcellulose, carboxymethylhydroxyethylcellulose, a vinyl sulfonated polymer, a hydratable graft polymer, or a mixture thereof.
 62. The method of claim 47 wherein the dispersant comprises a sodium salt of napthalene sulfonic acid, or a water-soluble polymer prepared by the caustic-catalyzed condensation of formaldehyde with acetone wherein the polymer contains sodium sulfate groups.
 63. The method of claim 47 wherein the dispersant is present in the fluid loss control additive in an amount sufficient to prevent gelation of the cement composition.
 64. The method of claim 47 wherein the iron compound is an iron chloride or an iron gluconate.
 65. The method of claim 64 wherein the iron chloride is ferrous chloride, ferric chloride, or a mixture thereof.
 66. The method of claim 47 wherein the fluid loss control additive further comprises a zeolite.
 67. The method of claim 66 wherein the zeolite further comprises chabazite and amorphous silica.
 68. The method of claim 66 wherein the zeolite is present in the fluid loss control additive in an amount in the range of from about 0.1% to about 15% by weight of the fluid loss control additive.
 69. The method of claim 66 wherein the fluid loss control additive further comprises an organic acid, a deaggregation agent, silica, or a combination thereof.
 70. The method of claim 47 wherein the fluid loss control additive further comprises a shale.
 71. The method of claim 70 wherein the shale comprises vitrified shale.
 72. The method of claim 70 wherein the fluid loss control additive further comprises a deaggregation agent, silica, or a combination thereof.
 73. The method of claim 72 wherein the silica is high surface area amorphous silica.
 74. The method of claim 73 wherein the high surface area amorphous silica is present in the fluid loss control additive in an amount sufficient to provide a desired after-set compressive strength.
 75. The method of claim 47 wherein the fluid loss control additive is present in the cement composition in an amount in the range of from about 0.01% to about 5% by weight of cement.
 76. The method of claim 47 wherein the acrylic acid copolymer derivative is present in the fluid loss control additive in an amount in the range of from about 30% to about 60% by weight.
 77. The method of claim 47 wherein the fluid loss control additive is present in the cement composition in an amount in the range of from about 0.01% to about 5% by weight of cement, the iron compound is present in the fluid loss control additive in an amount in the range of from about 10% to about 15% by weight of the fluid loss control additive, the hydratable polymer is present in the fluid loss control additive in an amount in the range of from about 1% to about 5% by weight of the fluid loss control additive, and the dispersant is present in the fluid loss control additive in an amount in the range of from about 20% to about 45% by weight of the fluid loss control additive.
 78. A cement composition comprising a cement, water, and a fluid loss control additive, the fluid loss control additive comprising: an acrylic acid copolymer derivative; an iron compound; and at least one of a dispersant or a hydratable polymer.
 79. The cement composition of claim 78 wherein the acrylic acid copolymer derivative comprises a copolymer or a copolymer salt that comprises first monomers formed from N,N-dimethylacrylamide, and second monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof.
 80. The cement composition of claim 79 wherein the copolymer or the copolymer salt has a N,N-dimethylacrylamide to 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof mole ratio of from about 1:4 to about 4:1.
 81. The cement composition of claim 79 wherein the copolymer or the copolymer salt has a weight average molecular weight of between about 75,000 daltons and about 300,000 daltons.
 82. The cement composition of claim 78 wherein the acrylic acid copolymer derivative comprises a graft polymer comprising a backbone comprising at least one of a lignin, a lignite, or their salts and a grafted pendant group comprising monomers formed from at least one of 2-acrylamido-2-methylpropane sulfonic acid, acrylonitrile, N,N-dimethylacrylamide, acrylic acid, or N,N-dialkylaminoethylmethacrylate.
 83. The cement composition of claim 78 wherein the acrylic acid copolymer derivative comprises a graft polymer comprising a backbone comprising at least one of derivatized cellulose, polyvinyl alcohol, polyethylene oxide, or polypropylene oxide, and a grafted pendant group comprising monomers formed from at least one of 2-acrylamido-2-methylpropane sulfonic acid, acrylonitrile, N,N-dimethylacrylamide, acrylic acid, or N,N-dialkylaminoethylmethacrylate.
 84. The cement composition of claim 78 wherein the acrylic acid copolymer derivative comprises a copolymer or a copolymer salt comprising first monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof.
 85. The cement composition of claim 84 wherein the copolymer or the copolymer salt comprises first monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof, second monomers formed from maleic acid or a salt thereof, third monomers formed from N-vinyl caprolactam, and fourth monomers formed from 4-hydroxybutyl vinyl ether.
 86. The cement composition of claim 84 wherein the copolymer or the copolymer salt comprises a copolymer comprising first monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof, and second monomers formed from hydrolyzed acrylamide.
 87. The cement composition of claim 78 wherein the acrylic acid copolymer derivative comprises a copolymer or copolymer salt comprising a waffle tannin having monomers formed from at least one of 2-acrylamido-2-methylpropane sulfonic acid or acrylamide grafted thereto.
 88. The cement composition of claim 78 wherein the acrylic acid copolymer derivative comprises 1 part by weight of a polymer comprising 70 mole % of AMPS, 17 mole % of N, N-dimethylacrylamide, and 13 mole % of acrylamide, and 2 parts by weight of hydroxyethylcellulose having 1.5 moles of ethylene oxide substitution.
 89. The cement composition of claim 78 wherein the acrylic acid copolymer derivative comprises a copolymer or copolymer salt of a vinylamide morpholine derivative and least one branched N-vinylamide derivative, wherein the vinylamide morpholine derivative is selected from compounds represented by the formula:

wherein R₁—H or —CH₃ and R₂ is —H, —CH₃, or —CH₂CH₃ and is positioned on any of the four carbon atoms in the morpholine ring, and the N-vinylamide derivative is selected from the compounds represented by the formula:

wherein R₃ is R₁—H or —CH₃; R₄ is —H, —CH₃, —CH₂CH₃, —CH(CH₃)₂, —(CH₃)₃, or —CH(CH₃)₂SO₃X, wherein X is —Na, —NH₄, or —Ca½, and R₅ is —H, —CH₃, or —CH₂CH₃.
 90. The cement composition of claim 89 wherein the vinylamide derivative is acryloylmorpholine, and the branched N-vinylamide derivative is a sodium salt of 2-acrylamido-2-methylpropanesulfonic acid.
 91. The cement composition of claim 89 wherein the vinylamide derivative is acryloylmorpholine, a first vinylamide derivative is a sodium salt of 2-acrylamido-2-methylpropanesulfonic acid, and a second vinylamide derivative is acrylamide.
 92. The cement composition of claim 78 wherein the hydratable polymer comprises carboxymethylcellulose, hydroxyethylcellulose, carboxymethylhydroxyethylcellulose, a vinyl sulfonated polymer, a hydratable graft polymer, or a mixture thereof.
 93. The cement composition of claim 78 wherein the hydratable polymer is present in the fluid loss control additive in an amount in the range of from about 0.1% to about 15% by weight of the fluid loss control additive.
 94. The cement composition of claim 78 wherein the dispersant comprises a sodium salt of napthalene sulfonic acid, or a water-soluble polymer prepared by the caustic-catalyzed condensation of formaldehyde with acetone wherein the polymer contains sodium sulfate groups.
 95. The cement composition of claim 78 wherein the dispersant is present in the fluid loss control additive in an amount sufficient to prevent gelation of the cement composition.
 96. The cement composition of claim 78 wherein the dispersant is present in the fluid loss control additive in an amount in the range of from about 5% to about 70% by weight of the fluid loss control additive.
 97. The cement composition of claim 78 wherein the iron compound is present in the fluid loss control additive in an amount in the range of from about 5% to about 25% by weight of the fluid loss control additive.
 98. The cement composition of claim 78 wherein the iron compound is present in the fluid loss control additive in an amount in the range of from about 10% to about 15% by weight of the fluid loss control additive.
 99. The cement composition of claim 78 wherein the iron compound is an iron chloride or an iron gluconate.
 100. The cement composition of claim 99 wherein the iron chloride is ferrous chloride, ferric chloride, or a mixture thereof.
 101. The cement composition of claim 78 wherein the fluid loss control additive further comprises a zeolite.
 102. The cement composition of claim 101 wherein the zeolite further comprises chabazite and amorphous silica.
 103. The cement composition of claim 101 wherein the zeolite is present in the fluid loss control additive in an amount in the range of from about 0.1% to about 15% by weight of the fluid loss control additive.
 104. The cement composition of claim 101 wherein the fluid loss control additive further comprises an organic acid, a deaggregation agent, silica, or a combination thereof.
 105. The cement composition of claim 78 wherein the fluid loss control additive further comprises a shale.
 106. The cement composition of claim 105 wherein the shale comprises vitrified shale.
 107. The cement composition of claim 105 wherein the shale is present in the fluid loss control additive in an amount in the range of from about 0.1% to about 15% by weight of the fluid loss control additive.
 108. The cement composition of claim 105 wherein the fluid loss control additive further comprises an organic acid, a deaggregation agent, silica, or a combination thereof.
 109. The cement composition of claim 108 wherein the organic acid is present in the fluid loss control additive in an amount sufficient to provide a desired degree of viscosity control.
 110. The cement composition of claim 108 wherein the organic acid is present in the fluid loss control additive in an amount in the range of from about 0.01% to about 5% by weight of the fluid loss control additive.
 111. The cement composition of claim 108 wherein the deaggregation agent is present in the fluid loss control additive in an amount sufficient to enable the fluid loss control additive to flow freely as a powder.
 112. The cement composition of claim 108 wherein the deaggregation agent is present in the fluid loss control additive in an amount in the range of from about 1% to about 15% by weight of the fluid loss control additive.
 113. The cement composition of claim 108 wherein the silica is high surface area amorphous silica.
 114. The cement composition of claim 113 wherein the high surface area amorphous silica is present in the fluid loss control additive in an amount sufficient to provide a desired after-set compressive strength.
 115. The cement composition of claim 113 wherein the high surface area amorphous silica is present in the fluid loss control additive in an amount in the range of from about 0.1% to about 15% by weight of the fluid loss control additive.
 116. The cement composition of claim 78 wherein the cement comprises a Portland cement, a pozzolanic cement, a gypsum cement, a high alumina content cement, a silica cement, or a high alkalinity cement.
 117. The cement composition of claim 78 wherein the water is present in the cement composition in an amount sufficient to form a pumpable slurry.
 118. The cement composition of claim 78 wherein the water is present in the cement composition in an amount in the range of from about 15% to about 200% by weight of cement.
 119. The cement composition of claim 78 wherein the cement composition has a density in the range of from about 5 pounds per gallon to about 30 pounds per gallon.
 120. The cement composition of claim 78 wherein the cement composition further comprises a weighting agent, a defoamer, a surfactant, mica, fiber, bentonite, microspheres, fumed silica, a salt, vitrified shale, fly ash, a dispersant, a retardant, or an accelerant.
 121. The cement composition of claim 78 wherein the fluid loss control additive is present in the cement composition in an amount sufficient to provide a desired degree of fluid loss control.
 122. The cement composition of claim 78 wherein the fluid loss control additive is present in the cement composition in an amount in the range of from about 0.01% to about 5% by weight of cement.
 123. The cement composition of claim 78 wherein the acrylic acid copolymer derivative is present in the fluid loss control additive in an amount in the range of from about 1% to about 99% by weight.
 124. The cement composition of claim 78 wherein the fluid loss control additive is present in the cement composition in an amount in the range of from about 0.01% to about 5% by weight of cement, the iron compound is present in the fluid loss control additive in an amount in the range of from about 10% to about 15% by weight of the fluid loss control additive, the hydratable polymer is present in the fluid loss control additive in an amount in the range of from about 1% to about 5% by weight of the fluid loss control additive, and the dispersant is present in the fluid loss control additive in an amount in the range of from about 20% to about 45% by weight of the fluid loss control additive.
 125. A fluid loss control additive comprising: an acrylic acid copolymer derivative; an iron compound; and at least one of a dispersant or a hydratable polymer.
 126. The fluid loss control additive of claim 125 wherein the acrylic acid copolymer derivative comprises a copolymer or a copolymer salt that comprises first monomers formed from N,N-dimethylacrylamide, and second monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof.
 127. The fluid loss control additive of claim 126 wherein the copolymer or the copolymer salt has a N,N-dimethylacrylamide to 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof mole ratio of from about 1:4 to about 4:1.
 128. The fluid loss control additive of claim 126 wherein the copolymer or the copolymer salt has a weight average molecular weight of between about 75,000 daltons and about 300,000 daltons.
 129. The fluid loss control additive of claim 125 wherein the acrylic acid copolymer derivative comprises a graft polymer comprising a backbone comprising at least one of a lignin, a lignite, or their salts and a grafted pendant group comprising monomers formed from at least one of 2-acrylamido-2-methylpropane sulfonic acid, acrylonitrile, N,N-dimethylacrylamide, acrylic acid, or N,N-dialkylaminoethylmethacrylate.
 130. The fluid loss control additive of claim 125 wherein the acrylic acid copolymer derivative comprises a graft polymer comprising a backbone comprising at least one of derivatized cellulose, polyvinyl alcohol, polyethylene oxide, or polypropylene oxide, and a grafted pendant group comprising monomers formed from at least one of 2-acrylamido-2-methylpropane sulfonic acid, acrylonitrile, N,N-dimethylacrylamide, acrylic acid, or N,N-dialkylaminoethylmethacrylate.
 131. The fluid loss control additive of claim 125 wherein the acrylic acid copolymer derivative comprises a copolymer or a copolymer salt comprising first monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof.
 132. The fluid loss control additive of claim 131 wherein the copolymer or the copolymer salt comprises first monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof, second monomers formed from maleic acid or a salt thereof, third monomers formed from N-vinyl caprolactam, and fourth monomers formed from 4-hydroxybutyl vinyl ether.
 133. The fluid loss control additive of claim 131 wherein the copolymer or the copolymer salt comprises a copolymer comprising first monomers formed from 2-acrylamido-2-methylpropane sulfonic acid or a derivative thereof, and second monomers formed from hydrolyzed acrylamide.
 134. The fluid loss control additive of claim 125 wherein the acrylic acid copolymer derivative comprises a copolymer or copolymer salt comprising a waffle tannin having monomers formed from at least one of 2-acrylamido-2-methylpropane sulfonic acid or acrylamide grafted thereto.
 135. The fluid loss control additive of claim 125 wherein the acrylic acid copolymer derivative comprises 1 part by weight of a polymer comprising 70 mole % of AMPS, 17 mole % of N, N-dimethylacrylamide, and 13 mole % of acrylamide, and 2 parts by weight of hydroxyethylcellulose having 1.5 moles of ethylene oxide substitution.
 136. The fluid loss control additive of claim 125 wherein the acrylic acid copolymer derivative comprises a copolymer or copolymer salt of a vinylamide morpholine derivative and least one branched N-vinylamide derivative, wherein the vinylamide morpholine derivative is selected from compounds represented by the formula:

wherein R₁—H or —CH₃ and R₂ is —H, —CH₃, or —CH₂CH₃ and is positioned on any of the four carbon atoms in the morpholine ring, and the N-vinylamide derivative is selected from the compounds represented by the formula:

wherein R₃ is R₁—H or —CH₃; R₄ is —H, —CH₃, —CH₂CH₃, —CH(CH₃)₂, —C(CH₃)₃, or —CH(CH₃)₂SO₃X, wherein X is —Na, —NH₄, or —Ca½, and R₅ is —H, —CH₃, or —CH₂CH₃.
 137. The fluid loss control additive of claim 136 wherein the vinylamide derivative is acryloylmorpholine and the branched N-vinylamide derivative is a sodium salt of 2-acrylamido-2-methylpropanesulfonic acid.
 138. The fluid loss control additive of claim 136 wherein the vinylamide derivative is acryloylmorpholine, a first vinylamide derivative is a sodium salt of 2-acrylamido-2-methylpropanesulfonic acid, and a second vinylamide derivative is acrylamide.
 139. The fluid loss control additive of claim 125 wherein the hydratable polymer comprises carboxymethylcellulose, hydroxyethylcellulose, carboxymethylhydroxyethylcellulose, a vinyl sulfonated polymer, a hydratable graft polymer, or a mixture thereof.
 140. The fluid loss control additive of claim 125 wherein the hydratable polymer is present in the fluid loss control additive in an amount in the range of from about 0.1% to about 15% by weight of the fluid loss control additive.
 141. The fluid loss control additive of claim 125 wherein the dispersant comprises a sodium salt of napthalene sulfonic acid, or a water-soluble polymer prepared by the caustic-catalyzed condensation of formaldehyde with acetone wherein the polymer contains sodium sulfate groups.
 142. The fluid loss control additive of claim 125 wherein the dispersant is present in the fluid loss control additive in an amount sufficient to prevent gelation of the fluid loss control additive.
 143. The fluid loss control additive of claim 125 wherein the dispersant is present in the fluid loss control additive in an amount in the range of from about 5% to about 70% by weight of the fluid loss control additive.
 144. The fluid loss control additive of claim 125 wherein the iron compound is present in the fluid loss control additive in an amount in the range of from about 5% to about 25% by weight of the fluid loss control additive.
 145. The fluid loss control additive of claim 125 wherein the iron compound is an iron chloride or an iron gluconate.
 146. The fluid loss control additive of claim 145 wherein the iron chloride is ferrous chloride, ferric chloride, or a mixture thereof.
 147. The fluid loss control additive of claim 125 wherein the fluid loss control additive further comprises a zeolite.
 148. The fluid loss control additive of claim 147 wherein the zeolite further comprises chabazite and amorphous silica.
 149. The fluid loss control additive of claim 147 wherein the zeolite is present in the fluid loss control additive in an amount in the range of from about 0.1% to about 15% by weight of the fluid loss control additive.
 150. The fluid loss control additive of claim 147 wherein the fluid loss control additive further comprises an organic acid, a deaggregation agent, silica, or a combination thereof.
 151. The fluid loss control additive of claim 125 wherein the fluid loss control additive further comprises a shale.
 152. The fluid loss control additive of claim 151 wherein the shale comprises vitrified shale.
 153. The fluid loss control additive of claim 151 wherein the shale is present in the fluid loss control additive in an amount in the range of from about 0.1% to about 15% by weight of the fluid loss control additive.
 154. The fluid loss control additive of claim 151 wherein the fluid loss control additive further comprises an organic acid, a deaggregation agent, silica, or a combination thereof.
 155. The fluid loss control additive of claim 154 wherein the organic acid is present in the fluid loss control additive in an amount sufficient to provide a desired degree of viscosity control.
 156. The fluid loss control additive of claim 154 wherein the organic acid is present in the fluid loss control additive in an amount in the range of from about 0.01% to about 5% by weight of the fluid loss control additive.
 157. The fluid loss control additive of claim 154 wherein the deaggregation agent is present in the fluid loss control additive in an amount sufficient to enable the fluid loss control additive to flow freely as a powder.
 158. The fluid loss control additive of claim 154 wherein the deaggregation agent is present in the fluid loss control additive in an amount in the range of from about 1% to about 15% by weight of the fluid loss control additive.
 159. The fluid loss control additive of claim 154 wherein the silica is high surface area amorphous silica.
 160. The fluid loss control additive of claim 159 wherein the high surface area amorphous silica is present in the fluid loss control additive in an amount sufficient to provide a desired after-set compressive strength.
 161. The fluid loss control additive of claim 159 wherein the high surface area amorphous silica is present in the fluid loss control additive in an amount in the range of from about 0.1% to about 15% by weight of the fluid loss control additive.
 162. The fluid loss control additive of claim 125 wherein the acrylic acid copolymer derivative is present in the fluid loss control additive in an amount in the range of from about 1% to about 99% by weight.
 163. The fluid loss control additive of claim 125 wherein the fluid loss control additive is present in the cement composition in an amount in the range of from about 0.01% to about 5% by weight of cement, the iron compound is present in the fluid loss control additive in an amount in the range of from about 10% to about 15% by weight of the fluid loss control additive, the hydratable polymer is present in the fluid loss control additive in an amount in the range of from about 1% to about 5% by weight of the fluid loss control additive, and the dispersant is present in the fluid loss control additive in an amount in the range of from about 20% to about 45% by weight of the fluid loss control additive. 